How do I reset service computer warning Audi A3 2009

Possibly reset issue.
Google "D3 service interval reset" for instructions.
It is probably through the menu system.

Service interval mileage is also selectable on A8's through the menu system. I very much doubt anyone has altered this.

NEED CODE FAULTS AND THE ECUS THAT THEY COME ON!!

"Retriger airbag control unit"??? NOT! If the airbags are deployed in a 2000 Audi A4, the airbag control unit MUST be replaced. Pleases refer to 2000 Audi A4 service information for more details.

This is a common fault with a number of performance cars, I have had it in a Jag, and an Audi

The light will go out if you have ALL bulbs working correctly and have the CORRECT bulbs installed. Check again.

oil and filtre to be changed ,have to be an audi dealer and when filtre and oil changed they put the light out and reset system

The warning light means there is a code waiting to be read.
There does not have to be anything wrong with the airbags themselves, for the system to be malfunctioning. It could be the inertial sensors. And yes it does have to be reset, but it is not really a computer. And a place like Autozone can easily read the codes and then reset them.

You'll have to have the computer scanned to see which bag tripped the light. Then you can reset it and see if it comes back. These cars will get fluke warnings like that sometimes, but if it comes back, you'll need to check the harness connectors for the offending airbag and possibly zip-tie them together to hold them and keep them from falsely tripping another warning.

1. Turn off the ignition
2. Press and hold the button on the left side of the display while turning the ignition on
3. Service OIL will be displayed
4. Pull out the button on the right side of the display until the service prompt is cleared
5. The display should now read ---
6. If the above procedure does not work, outlined below is an alternative procedure:
7. With the ignition off, push the right button
8. Turn the ignition on and then pull the left button
9. This should clear the warning message --- I have a 2002 A4 Quattro. To reset that Service message, hold down the service button. That's the one with the picture of a wrench on it. While holding it down, turn on the ignition. Let go of the service button and press the "Mode" button just to the right of the service button. It should clear the display.

* This does not work in older models, like my Audi A4 /1.6, 1995. It needs the cable and the program ( e.g. VAG-COM). Even with this, clearing the code (IN1 or IN2) is quite complicated.

Turn off the ignition press and hold the button on the leftside of the display while turning the ignition on it should say service oil on the display pull out the button on the rightside of the display until the service oil clears